Study on hazard assessment of mountainous flood in riverside country- a case study in Xinshan, Hubei, China

Abstract Mountainous riverside countries have already become the weaknesses of flood disaster control infrastructure in China, so flood calculation based on hydraulics models plays a key role in urban flood monitoring, warning and prevention. In order to validate the availability of a proposed one-dimension hydraulics flood model, the paper selects Xinshan County, Hubei Province, China as a typical study area. Considering the river distribution system and flood source analysis in Xinshan County, its flood scale and calculation scheme are then proposed. On the basis of HEC-RAS software, the one-dimension hydraulics model is constructed, which is applied to calculating the river flood evolutions and diffusing embankment processes with the designed flood probability of 0.01, 0.02, 0.05, 0.10, and 0.20 respectively. The comprehensive flood process information (such as diffuse area, diffuse duration and water depth) is also retrieved, which is used to calculate flood hazard and map flood hazard distribution. Calculation results reveal that the main parts of Gufu River basically meet the flood prevention standard of 0.05 (probability) in Xinshan County, while the intersection of Gufu River and Wangjia River has lower flood prevention ability than its flood prevention standard, which are basically consistent with local reality and flood estimation. Moreover, this fact proves that the proposed one-dimension hydraulics flood model is effective.